During the tumult of the American Civil War, Abraham Lincoln happily declared that ‘he was a party man and did not believe in any man who was not’. This remark to a conservative Democrat, and the allied belief of a radical Republican that ‘no man was ever more firmly or consistently the representative of a party than was Mr Lincoln’, are not quoted in Matthew Pinsker’s fine study of the 16th president’s political formation and party practice, but they capture the spirit of this important book.

Pinsker’s title is arresting. Yet, sworn in as the Republican president of a fractured nation in March 1861 – after seven southern states had broken away to form an independent Confederacy – Lincoln seemed ill-equipped to wield the power of his office. Few American presidents have had so little executive experience. He had been a legislator in the Illinois Assembly and in the US House of Representatives; he ran a law office not known for its efficiency. It was an open question as to who would guide the new administration. His experienced Republican rival, Secretary of State William Henry Seward, fancied taking the reins himself – until he came to see that he had underestimated the man who had beaten him to the presidency. As Lincoln settled into office, he led from the front and came to make all the key decisions himself: appointing and dismissing the Union’s generals, forging policies on slavery, emancipation and the political reconstruction of territory returned to Union control.

Although Lincoln shared his plans with his department heads, he only occasionally asked their advice. His ‘team of rivals’ was never a team of equals. The President’s secretaries, John Hay and John Nicolay, privately referred to him by the Japanese term then in vogue. ‘The Tycoon is in fine whack,’ Hay wrote in the summer of 1863. ‘I have rarely seen him more serene and busy. He is managing this war, the draft, foreign relations, and planning a reconstruction of the Union, all at once.’

Pinsker uses the term ‘boss’ to a different end, to describe Lincoln’s life’s work as a party builder and organiser. This talent for management, he claims, was a greater driving force in Lincoln’s career than the pursuit of office. ‘We don’t remember him as “Boss Lincoln,” but we should,’ Pinsker writes. The term is not anachronistic. From the 1850s, the bosses of Tammany Hall, a social and political organisation chiefly serving Irish Catholic immigrants, controlled Democratic Party nominations and patronage in Manhattan. Tammany would become a byword for corruption, notably after the war under the notorious pocket-liner Boss Tweed. Pinsker is at pains to stress that Lincoln was no Midwestern Tammany boss – rather, he was a maestro of ‘men and measures’, a contemporary phrase highlighting ‘the combination of patronage and policy considered essential to successful political movements’.

It should be remembered that the drafters of the federal constitution at Philadelphia in 1787 conceived of parties as unrepublican factions serving sectional interests. There is no mention of party in that foundational document. But by the time of Lincoln’s birth in 1809, state and national politics were commonly shaped by the two contending parties of that era, Democratic-Republicans and Federalists. Their conflict in the fraught presidential election of 1800 had established the principle of losers’ consent – the peaceful transfer of power – but only after the threat of armed conflict had been averted. Thereafter, until 1860, the defeated party in presidential elections accepted the outcome and prepared to fight another day.

The young Lincoln’s political world enjoyed something close to universal suffrage for adult white males, often achieved through fraud to circumvent the limitations on the right to vote, but legitimised after several states’ constitutional revisions from 1815 and 1821. Popular participation demanded partisan electoral machinery, for which Americans could draw on earlier models of coordinating committees, nominating conventions and party newspapers. During Lincoln’s 20th year, 1828, the presidential election between Andrew Jackson and John Quincy Adams generated excitement on a scale not known since 1800 and featured means of party organisation and mobilisation already well honed at state level.

This was the world that Lincoln entered as a candidate for the Illinois state legislature in 1832. Pinsker traces his role in forging three successive party organisations: the anti-­Jacksonian Whigs, the prewar antislavery Republicans and the wartime coalitional National Union Party. Lincoln’s strategic choices as a party leader, his shadowy private role and his focused and commanding correspondence are the meat of Boss Lincoln. Hundreds of letters, variously marked ‘Private’, ‘Strictly Confidential’, ‘For your eye only’ and ‘Burn this’, reveal Lincoln’s capacity for uncompromising politics, which the author analyses with relish.

Pinsker’s central theme is that over his career Lincoln learned to master the two competing partisan strategies of his time: ultraism and fusionism. Ultras were purists who focused on a core constituency (the base) or championed radical policies. Fusionists were pragmatists who looked outwards to broaden the movement through co-option and coalition. At first, Pinsker tells us, Lincoln moved from one strategy to another with a pronounced gear shift, but in time he came to alternate between them more smoothly.

Lincoln’s first run for office as an unaffiliated independent failed but two years later he won as a Whig, an enthusiast for the programme of economic nationalism articulated by the new party’s leader, Henry Clay of Kentucky. Clay’s vision of a commercial and manufacturing nation encouraged by credit facilities and linked by navigable waterways played especially well in aspiring western settlements keen to be connected to the market. One such was Lincoln’s New Salem, a small village on the Sangamon River, whose prospects depended on state-funded river and harbour improvements. The village soon failed but by then Lincoln, a self-taught lawyer and leader of the Whig legislative caucus, had moved twenty miles southeast to the growing town of Springfield, which he – as the savvy leader of the Sangamon delegation – succeeded in making the state capital.

Lincoln chose to leave the legislature in 1841 but for the next decade he remained an active Whig. He won a single term as a US congressman (1847–9) but that was not half the story. Party politics was above all the business of organisation, informal connections and popular mobilisation. In the historic presidential ‘hurrah’ campaign of 1840, arguably the first modern canvass in American history, Lincoln was a leading speaker, newspaper propagandist and strategist in the election of General William Henry Harrison. His confidential circular enjoining ‘watchfulness and labor’ in organising the whole state ‘so that every Whig can be brought to the polls’ laid out – in ten commandments – the duties of each county committee. His underlying principles still apply to this day. 

Pinsker presents Lincoln as a Whig fusionist who, when he grew frustrated with the party, turned to apply the same principle of broad coalition to the embryonic antislavery Republican Party. The story of his role in forming and leading the new party in Illinois during the 1850s, before switching to an ultraist strategy and becoming the Republican nominee for the presidency in 1860 is told with a formidable mastery of the sources, shrewd insight and compelling verve. 

In 1850 a political compromise – more accurately an armistice – calmed the North–South sectional crisis brought on by an American military land grab from Mexico that raised the prospect of slavery spreading into a region where it had been forbidden by law. It accepted that the principle of ‘popular sovereignty’ should give the settlers themselves the power to decide. However, this political calm was shattered in 1854 when Senator Stephen Douglas of Illinois, a Democrat, introduced a bill to organise the two territories of Kansas and Nebraska, acquired half a century earlier by purchase from France. Slavery had been prohibited there by the 1820 Missouri Compromise, but Douglas’s measure voided it by applying the doctrine of popular sovereignty. Even before it became law, the bill’s overreach prompted a political earthquake.

Lincoln saw the potential for a new political party that would embrace Whigs, radical antislavery ‘Free Soilers’ and those Democrats raging at Douglas for licensing slavery in the prairies. Fusion, Lincoln saw, would be a delicate business, a matter of bringing together previous enemies, uniting radicals with moderates. In a photograph taken in 1854, he is clutching a newspaper, the Chicago Democrat: more than a stage prop, it aligned a leading former Whig with the most important anti-Nebraska Democratic newspaper in Illinois. Regular Democrats recognised him as the ‘Goliath of the anti-Nebraska black republican fusionists’, a role in which, Pinsker persuasively shows, he deployed ‘deft manipulation, blunt intimidation, or thoughtful argument’. Fundamental to his project, however, was a profound moral repudiation of slavery, centred on the natural rights principles of the Declaration of Independence.

Later, Lincoln switched from pragmatic fusion to steely ultraism. He was impelled initially by the Supreme Court’s shocking ruling in the Dred Scott case that black people had no rights as federal citizens and that Congress could not constitutionally prohibit slavery in the nation’s territories. Calling the verdict ‘a burlesque upon judicial decisions’, he vowed it must be overruled. Later, a deep split in the Democratic Party between Douglas and President James Buchanan over slavery policy in Kansas created a shockwave that encouraged some Republicans to propose an alliance with the Illinois senator. Alarmed, Lincoln warned his party against coalescing with Douglas Democrats: their moral neutrality over slavery was at odds with purists’ insistence that the institution was a wrong and must be demolished. Lincoln won the argument and fought his campaign for the US Senate in 1858 as a Republican ultra. Although defeated, he carried the same strategy forward into his successful run for president in 1860.

Pinsker skilfully uses this binary framework to plot President Lincoln’s course as the Union’s wartime commander-in-chief. Here his story is familiar, though it takes on added colour in the light of his rich prewar narrative. Lincoln initially pursued a fusionist strategy to create the widest possible political coalition within the fiercely patriotic North. Elections to state and federal office continued largely uninterrupted throughout the conflict, with Lincoln and his Republicans rebranding themselves as the Union Party and drawing in War Democrats and some conservatives from the loyal slaveholding states. The book’s focus on the Boss necessarily understates the part played by other agents of this centrist strategy, notably the loyal states’ governors, whose role has been celebrated in rich recent scholarship. 

The Union army’s humiliating failures in the summer of 1862 led Lincoln to shift towards political ultraism by adopting a radical emancipation policy to undermine the Confederate economy. For the President, from that point onwards, the distinction between a war for the Union and one for human freedom ended. Two years later, with Union and Confederate forces embroiled in a Virginia bloodbath and no end to the war in sight, Lincoln came under enormous pressure to abandon ultraism and pursue peace without emancipation. He did not yield.